1. Field of the Invention
The present invention relates to a method of manufacturing a stator coil, and more particularly, relates to a method of manufacturing a stator coil used in a stator of a rotary electric machine.
2. Background Art
In recent years, rotary electric machines used as electric motors and alternators are required to be of compact high-output and high quality.
For example, a space to install a vehicle mount rotary electric machine is becoming smaller and smaller, while on the other hand, increase of output is being required.
As a conventional rotary electric machine, there is known the one in which the stator coil used in the stator is constituted of continuous windings (For example, refer to Patent documents 1 and 2).    [Patent document 1] Japanese Patent Application Laid-open No. 2002-176752    [Patent document 2] Japanese Patent Application Laid-open No. 2004-320886
Methods of manufacturing such stator coils constituted of continuous windings includes the ones described below, for example.
First, a shaped body constituted of a plurality of parallel straight portions connected by a plurality of turn portions is formed from a plurality of electric conductor wires. Next, these shaped bodies are combined with one another to form a combined body. Each of the shaped body sets constituting the combined body includes, in the longitudinal direction of the combined body, a plurality of straight overlap sections formed of a plurality of the straight portions of one shaped body and a plurality of the straight portions of another shaped body which are respectively overlapped with each other. Accordingly, in this combined body, a plurality of the straight overlap sections are aligned in the longitudinal direction of the combined body. Next, this combined body is wound around a core member by a predetermined number of turns to form a wound body. This wound body includes, in the circumferential direction, a plurality of straight laminated sections constituted of a plurality of the straight overlap sections of one shaped body set laminated in the radial direction.
Thus obtained wound body is made as a stator coil, the respective straight laminated sections being disposed in the slots of the stator core, the respective turn portions being disposed outside the slots.
However, in the above manufacturing method, it is likely that the overlap of the straight portions in the straight overlap section of the combined body becomes out of alignment, or distances between adjacent straight overlap sections become non-uniform when the combined body is wound around the core member. Accordingly, in the obtained wound body, it is likely that the overlap of a plurality of the straight portions in the straight laminated section becomes out of alignment, or distance between the adjacent straight laminated sections becomes non-uniform. In this case, it is likely that the orientation accuracy of the respective straight portions in the slots is lowered, or distance (pitch) between the straight laminated sections disposed in the adjacent slots becomes non-uniform when the straight laminated sections of the stator coil are disposed in the slots of the stator core. Lowering of the orientation accuracy of the straight portions or non-uniformity of the pitch leads to lowering of the slot occupation factor of the stator, or the output of the rotary electric machine using this stator.